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Sara Öberg

Assistant professor

About me

I am interested in the causes and consequences of reproductive challenges, i.e. threats to the conception and development of healthy offspring. My research covers aspects across the spectrum from pre-conception through pregnancy and up to delivery. The vast majority of my work is collaborative, whether involving individual experts or working in teams and larger networks.

Research description

Reproduction is the beginning of life, and the time we spend in utero inarguably the most important developmental period of our lives. Disruptions or insults during this critical time could, through direct or down-stream effects, impair offspring health both in the short and long-term. My research spans across the whole the range of sensitive periods, from pre-conception through pregnancy up to labour and delivery, and concerns the health of both mother and offspring.

Early life origins of later health and disease

To make meaningful inference from observational data, and ultimately identify modifiable risk factors, it is vital to understand and address threats to study validity. In my thesis work I used twins to exclude the potentially confounding influence of shared genetic and environmental factors on well-established associations between birth weight and adult health outcomes (cardiovascular disease and breast cancer). Extending this work I also explored whether twins’ health differs from singletons’ (which could be expected on account of a strained intrauterine experience, sharing space and supply line), by contrasting twins and singletons of twin families, and singletons of twin and non-twin families respectively. Continued investigations of early life factors and later health are currently mainly focused on offspring neurodevelopment, through collaboration with Indiana University.

Familial clustering of pregnancy complications

The unique information in Swedish population registers can be used to explore clustering of various pregnancy complications, to provide clues about underlying mechanisms and familial susceptibility. For postpartum hemorrhage, our finding of similar patterns of recurrence regardless of triggering mechanism (e.g. uterine atony, retained placenta, lacerations) suggests a common underlying liability to bleed. By considering different family clusters we have quantified the role of shared environment, maternal and fetal genetic factors for this liability, as well as for post-term birth. Familial clustering studies are currently focused on the liability for birth defects, while further studies are planned to advance our understanding of the causes and consequences of postpartum hemorrhage.

Infertility, fertility treatments in the Swedish population

Involuntary childlessness is prevalent and increasing in many countries, and the subsequent use of ART thus expected to continue to rise (with 5% of Nordic births currently due to ART). The effect this may have for offspring health is still not fully known, in part due to limited large-scale follow-up through childhood, adolescence, and early adulthood, but also lingering methodological challenges. Rigorous evaluation is required to establish whether potential adverse effects are due to the treatments (ART) or rather related to their indication (infertility). Further disentangling the extent risks are due to potentially unavoidable events, such as multiple and preterm birth, can also improve etiological insight and assist clinical decision-making both pre- and post-conception. After first evaluating the role of multiple births in fertility treatment influence on pregnancy complications, my main research effort now focuses on expanding this work to evaluate long-term outcomes, and ideally consider both common (asthma, ADHD) and more rare conditions (diabetes and depression).


Current supervision of students 

  • Chen Wang
  • Ayesha Sujan (co-advisor, PhD-student, Indiana University)
  • Kelsey Wiggs (co-advisor, PhD-student, Indiana University)
  • Eva Skärby (Medical student, Karolinska Institutet)
  • Mausumi Das (MPH-student, Harvard Chan)

Previous supervision of students

  • Rossana Calderon (MPH-student, Harvard Chan)
  • John Lowery ( MPH-student, Harvard Chan)
  • Davide Attebrant-Sbrzesny (Medical student, Karolinska Institutet)



I have received funding from the National Institutes of Health, FORTE, the Swedish Research Council (VR), Fulbright, Lennander’s stiftelse, Wallenius’ stiftelse, Karolinska Institutet and Iris.



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  • Sjölander A, Frisell T, Oberg S. Causal interpretation of between-within models for twin studies. Epidemiologic Methods 2012 Aug;1(1): 217–237.
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Letters / Responses to letters

Oberg AS, Bateman BT. Genetics and Postpartum Hemorrhage: Author’s response to Sholapurkar. BMJ 2014; 349:g6210


Oberg AS. Health Consequences of Adverse Fetal Growth – Studies in Twins. Doctoral Thesis Karolinska Institutet, 2011. IBAN: 978-91-7457-371-8.


MD (2002) Karolinska Institutet

PhD (2011) Karolinska Institutet

MPH (2009) Harvard T.H. Chan School of Public Health


Academic positions

Postdoc research fellow (2011-2016), Harvard T.H. Chan School of Public Health 

Curriculum fellow (2015-2016), Harvard T.H. Chan School of Public Health 

Assistant professor (2016-) Karolinska Institutet

Adjunct assistant professor (2016-), Harvard T.H. Chan School of Public Health

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